The mean score

  1. In a class of 20 students, 19 of them took an exam in class and 1 student took a make-up exam the
    following day. The professor graded the first batch of 19 exams and found a mean score of 71 points with
    a standard deviation of 7.5 points. The student who took the make-up the following day scored 82 points
    on the exam.
    a) Does the new student’s score increase or decrease the mean score? Give a qualitative argument
    without calculations.
    b) Formally compute the new mean. Show your work. [For students wanting to play with fancier
    equations in R, use $$\frac {numerator}{denominator}$$ to define a fraction. To get a
    bar over a letter, use $$\bar x$$. To get a subscript, such as s[x], use $$s_{x}$$. These
    various commands can be combined such as $$\bar x = \frac {1+2+3}{3} = 2$$. $$
    puts equations on their own line, whereas use $ for inline equations.
    c) Does the new student’s score increase or decrease the standard deviation of the scores? Explain.